Lifting magnet



June 24, 1930. F. w; JESSOP 1,767,458

LIFT ING MAGNET Filed Jan. 13, 1950 Fig. 2. H ,3

BY M M MM ATTORNEYS.

INVENTOR.

Patented June 24, 1930 UNITED STATES PATENT OFFICE FRANCIS w. mssor, 0.1CLEVELAND unrsnrs, omo, nssrsnoa r run 0310 nrncrnrc RQIQLEQB MPA Y FEVE N 9 1 OR AT O OF H O LIFHHG MAGNET Application filed January 13,1930. Serial 110.420.377.

This invention relates to an electric lifting magnet of the type usedfor handling scrap iron and the like.

In the use of magnets of this type it has been found that there is atendency for the shoulders corresponding to shoulders 11 and 13, seen inFig. 2 of the drawings, to wear away completely as indicated by thedotted line A which causes loosening or warping of the non-magneticplate corresponding to 21 in the drawings with the consequence of damageto the electric coil and to the plate and a much reduced life of themagnet as compared with one in which provision is made to avoid thedifliculty. The principal object of this invention is to provide by asimple mechanism for the overcoming of this difiiculty.

Referring to the drawings, Fig. 1 is a bottom plan view of a magnetembodying my improvement; and Fig, 2 is a fragmentary sectional viewcorresponding substan,- tially to a section on line 2-1-2 of Fig. 1.

The magnet comprises the central pole piece 10, the outer annular polepiece 12, and an upper plate 14 to which such pole pieces are attached.The pole pieces 10 and 12 and the upper plate 14: are composed ofmaterial of high magnetic susceptibility, preferably cast steel or thelike. The central pole piece is provided with a shoulder 11 extendingoutwardly and the annular outer pole piece is provided with acorresponding shoulder 13 extending inwardly. These two pole pieces areattached to the plate 14 by means of suitable studs 16 and 18 extendingtherethrou h. The plate 14 is also provided with a ss 17 adapted toanchor the samefirmly to the central pole piece. An upstanding rib l9havi a hole 20 drilled therein is provided for the attachment of asuitable chain which cooperating with two or more similar ribs serves asmeans for attaching the m at to a lifting device. Supported on the soulders 11 and 13 is a plate 21 composed of material of high magneticreluctance, preferably manganese steel, since that material also gives agreat resistance to abrasion. Positioned in the space between the plates14 and 2 1 is a suitable coil designated by C and adapted to magnetizethe pole pieces, causing a magnetic circuit from one of the pole piecesthrough the plate l t to the other pole piece and across the gap betweenthe shoulders 11 and 13. Since the plate 21 has high magnetic reluctancethere will be a great tendency to hold pieces of ferrous metal betweenthe pole pieces and against the plate 21. It has been found in practicethat a considerable abrasion of the pole pieces results from themagnetic action upon the material handled causing same to be pulled intomore or less violent contact with the pole pieces and the plate 21. Theplate 21 being of much tougher metal than the pole pieces suffers theleast damage and when provided with the annular ribs 22 and 23 serves toprevent the abrasion on the pole pieces from cutting away the shoulders11 and 13 entirely. It has been found that when these ribs arenotprovided the shoulders will be cut away along lines correspondingsomewhat to the line A although the Wear on the two shoulders issomewhat unequal. When a large portion of one of the shoulders wearsaway ahead of the other the result is in many cases a warping of theplate 21 which causes one edge thereof to be loosened which not onlydamages the r plate but may cause very serious damage to the coil 0 byreason of water and other foreign material entering. The most importantfeature of the present invention is the provision of the ribs 22 and 23which,

being much tougher than the pole pieces, tend to prevent the shouldersfrom wearing away, causing wear corresponding somewhat to the dottedline B and giving a much greater life to the magnet than would beobtained without said ribs.

While I have not shown the leads to the coil C nor the electricalconnections, it is obvious that these may be of usual construction wellknown to those skilled in the art.

Having thus described my invention, what I claim is 1. A lifting magnetincluding spaced pole-pieces composed of material of high magneticsusceptibility, means for attaching said pole-pieces together, ashoulder carried by each of said pole pieces, a plate composed ofmaterial of high magnetic reluctance carried by said shoulders and meanstending to cause a magnetic flux between said spaced pole-pieces, saidplate having a projection near one of said pole-pieces.

2. A lifting magnet including spaced pole-pieces composed of material ofhigh magnetic susceptibility, means for attaching said pole-piecestogether, a shoulder carried by each of said pole-pieces, a platecomposed of material of high magnetic reluctance carried by saidshoulders and means tending to cause a magnetic flux between said spacedpole-pieces, said plate having a projection near one of said polepieces,said plate being composed of a material more resistant to abrasion thansaid pole-pieces.

3. A lifting magnet including spaced pole-pieces composed of material ofhigh magnetic susceptibility, means for attaching said pole-piecestogether, a shoulder carried by each of said pole-pieces, a platecomposed of material of high magnetic reluctance carried by saidshoulders and means tending to cause a magnetic flux between said spacedpole-pieces, said plate having a projection near one of saidpole-pieces, said plate being composed of manganese steel.

4. A lifting magnet including spaced pole-pieces composed of material ofhigh magnetic susceptibility, means for attaching said pole-piecestogether, a shoulder carried by each of said pole-pieces, a platecomposed of material of high magnetic reluctance carried by saidshoulders and means tending to cause a magnetic flux between said spacedpole-pieces, said plate having a projection near each of saidpole-pieces.

5. A lifting magnet including spaced pole-pieces composed of material ofhigh magnetic susceptibility, means for attaching said pole-piecestogether, a shoulder carried by each of said pole-pieces, a platecomposed of material of high magnetic reluctance carried by saidshoulders and means tending to cause a magnetic flux between said spacedpole-pieces, said plate having a projection near each of saidpole-pieces, said plate being composed of a material more resistant toabrasion than said pole-pieces.

6. A lifting magnet including spaced pole-pieces composed of material ofhigh magnetic susceptibility, means for attaching said pole-piecestogether, a shoulder carried by each of said pole-pieces, a platecomposed oi material of high magnetic reluctance carried by saidshoulders and means tending to cause a magnetic flux between said spacedpole-pieces, said plate having a projection near each of saidpole-pieces, said plate being composed of manganese steel.

7. A lifting magnet including a circular central pole-piece and a spacedannular pole piece concentric therewith, said pieces being composed of aferrous metal of high magnetic susceptibility, an upper plate composedof material having the same characteristics and connecting saidpole-pieces, an outer shoulder on said central piece and an innershoulder on said annular piece, an annular plate composed of material ofhigh magnetic reluctance and resting on said shoulders, said platehaving an annular rib near one of said pole- )ieces.

8. A li ting magnet including a circular central pole-piece and a spacedannular pole piece concentric therewith, said pieces being composed of aferrous metal of high magnetic susceptibility, an upper plate composedof material having the same characteristics and connecting saidpole-pieces, an outer shoulder on said central piece and an innershoulder on said annular piece, an annular plate composed of material ofhigh magnetic reluctance and resting on said shoulders, said platehaving an annular rib near each of said pole-pieces.

9. A lifting magnet including a circular central pole-piece and a spacedannular polepiece concentric therewith, said pieces being composed of aferrous metal of high magnetic susceptibility, an upper plate composedof material having the same characteristics and connecting saidpole-pieces, an outer shoulder on said central piece and an innershoulder on said annular piece, an annular plate composed of material ofhigh magnetic reluctance and resting on said shoulders, said platehaving an annular rib near one of said pole-pieces, said plate beingcomposed of manganese steel.

10. A lifting magnet including a circular central pole-piece and aspaced annular polepiece concentric therewith, said ieces being composedof a ferrous metal of ighmagnetic susceptibility, an upper platecomposed of material having the same characteristics and connecting saidpole-pieces, an outer shoulder on said central piece and an innershoulder on said annular piece, an annular plate composed of material ofhigh magnetic reluctance and resting on said shoulders, said platehaving an annular rib near each of said pole-pieces, said plate beingcomposed of manganese steel.

11. As a sub-combination of an electric lifting magnet, an annular plateof material of high magnetic reluctance having a pro jefcting portionspaced from an edge there- 0 12. As a sub-combination of an electriclifting magnet, an annular plate of material of high magnetic reluctancehaving a projecting portion spaced from each edge thereof.

13. As a sub-combination of an electric lifting magnet, an annular plateof material of high magnetic reluctance havin jectin annular rib portionspaced edge t ereof.

14. As a sub-combination of an electric lifting magnet, an annular plateof material of high magnetic reluctance having a proj ecting annular ribportion spaced from each edge thereof. a

15. As a sub-combination of an electric lifting magnet, an annular plateof manganese steel havin a pro ecting portlon spaced from an e gethereof.

16. As a sub-combination of an electric lifting magnet, an annular plateof manganese steel having a projecting portion spaced from each edgethereof.

17. As a sub-combination of an electric lifting magnet, an annular plateof manganese steel havin a projecting annular rib portion spaced ilOl'Ilan ed e thereof.

18. As a sub-combination 0 an electric lifting magnet, an annular plateof manganese steel having a projecting annular rib portion spaced fromeach edge thereof.

In testimony whereof, I hereunto afiix my signature.

FRANCIS W. JESSOP.

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